On-screen keyboards in Tkinter

I'm playing around with some Python and tKinter and have been wrestling with the idea of an on-screen keyboard that outputs keys-pressed to a text field.

I'm familiar with calculators and button input, but would anyone have some thoughts on designing an on-screen keyboard? I'm thinking that I will need to create a button for each letter, then place that in a grid, and then for each key define a separate command link. Which would result in a wholeee lotta code.

Your work is in the creation of the button_list and putting the keys into the right row and column in the grid.

I found similar code last night after I posted and did put things together quite well. Now it's just a matter of figuring out how then to link an Entry field with the keyboard. Without posting more code, tell me this if you don't mind: For taking commands from the on-screen keyboard should I look to .set() and .get() for placing that information in an Entry box, or should I refer to the Entry box by a variable and concatenate a string inside?